Ukraine in the early 90s hardly saw Russia as an adversary. After are all they invaded Moldova together.
Also back in the early 90s spending massive amounts of money you can't afford when your country is in an extremely horrible spot economically just in case you might need it 20 years later doesn't seem politically feasible (i.e. you need to be an authoritarian shithole like one of the countries you mentioned or slightly less authoritarian but consider a much larger neighbouring country to be an existential threat which again.. didn't make much sense in the early 90s)
PS: Kasachstan bought some 3 months ago and how the music has shifted. Enjoy your frozzen jail, with nuclear armed neighbors as guard.